Network Working Group K. McCloghrie
Request for Comments: 1213 Hughes LAN Systems, Inc.
Obsoletes: RFC 1158 M. Rose
Performance Systems International
Editors
March 1991
Management Information Base for Network Managementof TCP/IP-based internets:MIB-II
Status of this Memo
This memo defines the second version of the Management Information
Base (MIB-II) for use with network management protocols in TCP/IP-
based internets. This RFC specifies an IAB standards track protocol
for the Internet community, and requests discussion and suggestions
for improvements. Please refer to the current edition of the "IAB
Official Protocol Standards" for the standardization state and status
of this protocol. Distribution of this memo is unlimited.
Table of Contents
1. Abstract............................................... 22. Introduction .......................................... 23. Changes from RFC 1156 ................................. 33.1 Deprecated Objects ................................... 33.2 Display Strings ...................................... 43.3 Physical Addresses ................................... 43.4 The System Group ..................................... 53.5 The Interfaces Group ................................. 53.6 The Address Translation Group ........................ 63.7 The IP Group ......................................... 63.8 The ICMP Group ....................................... 73.9 The TCP Group ........................................ 73.10 The UDP Group ....................................... 73.11 The EGP Group ....................................... 73.12 The Transmission Group .............................. 83.13 The SNMP Group ...................................... 83.14 Changes from RFC 1158 ................. ............. 94. Objects ............................................... 104.1 Format of Definitions ................................ 105. Overview .............................................. 106. Definitions ........................................... 126.1 Textual Conventions .................................. 126.2 Groups in MIB-II ..................................... 136.3 The System Group ..................................... 13SNMP Working Group [Page 1]

RFC 1213 MIB-II March 19916.4 The Interfaces Group ................................. 166.5 The Address Translation Group ........................ 236.6 The IP Group ......................................... 266.7 The ICMP Group ....................................... 416.8 The TCP Group ........................................ 466.9 The UDP Group ........................................ 526.10 The EGP Group ....................................... 546.11 The Transmission Group .............................. 606.12 The SNMP Group ...................................... 607. Acknowledgements ...................................... 678. References ............................................ 699. Security Considerations ............................... 7010. Authors' Addresses ................................... 701. Abstract
This memo defines the second version of the Management Information
Base (MIB-II) for use with network management protocols in TCP/IP-
based internets. In particular, together with its companion memos
which describe the structure of management information (RFC 1155)
along with the network management protocol (RFC 1157) for TCP/IP-
based internets, these documents provide a simple, workable
architecture and system for managing TCP/IP-based internets and in
particular the Internet community.
2. Introduction
As reported in RFC 1052, IAB Recommendations for the Development of
Internet Network Management Standards [1], a two-prong strategy for
network management of TCP/IP-based internets was undertaken. In the
short-term, the Simple Network Management Protocol (SNMP) was to be
used to manage nodes in the Internet community. In the long-term,
the use of the OSI network management framework was to be examined.
Two documents were produced to define the management information: RFC1065, which defined the Structure of Management Information (SMI)
[2], and RFC 1066, which defined the Management Information Base
(MIB) [3]. Both of these documents were designed so as to be
compatible with both the SNMP and the OSI network management
framework.
This strategy was quite successful in the short-term: Internet-based
network management technology was fielded, by both the research and
commercial communities, within a few months. As a result of this,
portions of the Internet community became network manageable in a
timely fashion.
As reported in RFC 1109, Report of the Second Ad Hoc Network
Management Review Group [4], the requirements of the SNMP and the OSI
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RFC 1213 MIB-II March 1991
network management frameworks were more different than anticipated.
As such, the requirement for compatibility between the SMI/MIB and
both frameworks was suspended. This action permitted the operational
network management framework, the SNMP, to respond to new operational
needs in the Internet community by producing this document.
As such, the current network management framework for TCP/IP- based
internets consists of: Structure and Identification of Management
Information for TCP/IP-based internets, RFC 1155 [12], which
describes how managed objects contained in the MIB are defined;
Management Information Base for Network Management of TCP/IP-based
internets: MIB-II, this memo, which describes the managed objects
contained in the MIB (and supercedes RFC 1156 [13]); and, the Simple
Network Management Protocol, RFC 1098 [5], which defines the protocol
used to manage these objects.
3. Changes from RFC 1156
Features of this MIB include:
(1) incremental additions to reflect new operational
requirements;
(2) upwards compatibility with the SMI/MIB and the SNMP;
(3) improved support for multi-protocol entities; and,
(4) textual clean-up of the MIB to improve clarity and
readability.
The objects defined in MIB-II have the OBJECT IDENTIFIER prefix:
mib-2 OBJECT IDENTIFIER ::= { mgmt 1 }
which is identical to the prefix used in MIB-I.
3.1. Deprecated Objects
In order to better prepare implementors for future changes in the
MIB, a new term "deprecated" may be used when describing an object.
A deprecated object in the MIB is one which must be supported, but
one which will most likely be removed from the next version of the
MIB (e.g., MIB-III).
MIB-II marks one object as being deprecated:
atTable
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RFC 1213 MIB-II March 1991
As a result of deprecating the atTable object, the entire Address
Translation group is deprecated.
Note that no functionality is lost with the deprecation of these
objects: new objects providing equivalent or superior functionality
are defined in MIB-II.
3.2. Display Strings
In the past, there have been misinterpretations of the MIB as to when
a string of octets should contain printable characters, meant to be
displayed to a human. As a textual convention in the MIB, the
datatype
DisplayString ::=
OCTET STRING
is introduced. A DisplayString is restricted to the NVT ASCII
character set, as defined in pages 10-11 of [6].
The following objects are now defined in terms of DisplayString:
sysDescr
ifDescr
It should be noted that this change has no effect on either the
syntax nor semantics of these objects. The use of the DisplayString
notation is merely an artifact of the explanatory method used in
MIB-II and future MIBs.
Further it should be noted that any object defined in terms of OCTET
STRING may contain arbitrary binary data, in which each octet may
take any value from 0 to 255 (decimal).
3.3. Physical Addresses
As a further, textual convention in the MIB, the datatype
PhysAddress ::=
OCTET STRING
is introduced to represent media- or physical-level addresses.
The following objects are now defined in terms of PhysAddress:
ifPhysAddress
atPhysAddress
ipNetToMediaPhysAddress
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RFC 1213 MIB-II March 1991
It should be noted that this change has no effect on either the
syntax nor semantics of these objects. The use of the PhysAddress
notation is merely an artifact of the explanatory method used in
MIB-II and future MIBs.
3.4. The System Group
Four new objects are added to this group:
sysContact
sysName
sysLocation
sysServices
These provide contact, administrative, location, and service
information regarding the managed node.
3.5. The Interfaces Group
The definition of the ifNumber object was incorrect, as it required
all interfaces to support IP. (For example, devices without IP, such
as MAC-layer bridges, could not be managed if this definition was
strictly followed.) The description of the ifNumber object is
changed accordingly.
The ifTable object was mistaken marked as read-write, it has been
(correctly) re-designated as not-accessible. In addition, several
new values have been added to the ifType column in the ifTable
object:
ppp(23)
softwareLoopback(24)
eon(25)
ethernet-3Mbit(26)
nsip(27)
slip(28)
ultra(29)
ds3(30)
sip(31)
frame-relay(32)
Finally, a new column has been added to the ifTable object:
ifSpecific
which provides information about information specific to the media
being used to realize the interface.
SNMP Working Group [Page 5]

RFC 1213 MIB-II March 19913.6. The Address Translation Group
In MIB-I this group contained a table which permitted mappings from
network addresses (e.g., IP addresses) to physical addresses (e.g.,
MAC addresses). Experience has shown that efficient implementations
of this table make two assumptions: a single network protocol
environment, and mappings occur only from network address to physical
address.
The need to support multi-protocol nodes (e.g., those with both the
IP and CLNP active), and the need to support the inverse mapping
(e.g., for ES-IS), have invalidated both of these assumptions. As
such, the atTable object is declared deprecated.
In order to meet both the multi-protocol and inverse mapping
requirements, MIB-II and its successors will allocate up to two
address translation tables inside each network protocol group. That
is, the IP group will contain one address translation table, for
going from IP addresses to physical addresses. Similarly, when a
document defining MIB objects for the CLNP is produced (e.g., [7]),
it will contain two tables, for mappings in both directions, as this
is required for full functionality.
It should be noted that the choice of two tables (one for each
direction of mapping) provides for ease of implementation in many
cases, and does not introduce undue burden on implementations which
realize the address translation abstraction through a single internal
table.
3.7. The IP Group
The access attribute of the variable ipForwarding has been changed
from read-only to read-write.
In addition, there is a new column to the ipAddrTable object,
ipAdEntReasmMaxSize
which keeps track of the largest IP datagram that can be re-assembled
on a particular interface.
The descriptor of the ipRoutingTable object has been changed to
ipRouteTable for consistency with the other IP routing objects.
There are also three new columns in the ipRouteTable object,
ipRouteMask
ipRouteMetric5
ipRouteInfo
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RFC 1213 MIB-II March 1991
the first is used for IP routing subsystems that support arbitrary
subnet masks, and the latter two are IP routing protocol-specific.
Two new objects are added to the IP group:
ipNetToMediaTable
ipRoutingDiscards
the first is the address translation table for the IP group
(providing identical functionality to the now deprecated atTable in
the address translation group), and the latter provides information
when routes are lost due to a lack of buffer space.
3.8. The ICMP Group
There are no changes to this group.
3.9. The TCP Group
Two new variables are added:
tcpInErrs
tcpOutRsts
which keep track of the number of incoming TCP segments in error and
the number of resets generated by a TCP.
3.10. The UDP Group
A new table:
udpTable
is added.
3.11. The EGP Group
Experience has indicated a need for additional objects that are
useful in EGP monitoring. In addition to making several additions to
the egpNeighborTable object, i.e.,
egpNeighAs
egpNeighInMsgs
egpNeighInErrs
egpNeighOutMsgs
egpNeighOutErrs
egpNeighInErrMsgs
egpNeighOutErrMsgs
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RFC 1213 MIB-II March 1991
egpNeighStateUps
egpNeighStateDowns
egpNeighIntervalHello
egpNeighIntervalPoll
egpNeighMode
egpNeighEventTrigger
a new variable is added:
egpAs
which gives the autonomous system associated with this EGP entity.
3.12. The Transmission Group
MIB-I was lacking in that it did not distinguish between different
types of transmission media. A new group, the Transmission group, is
allocated for this purpose:
transmission OBJECT IDENTIFIER ::= { mib-2 10 }
When Internet-standard definitions for managing transmission media
are defined, the transmission group is used to provide a prefix for
the names of those objects.
Typically, such definitions reside in the experimental portion of the
MIB until they are "proven", then as a part of the Internet
standardization process, the definitions are accordingly elevated and
a new object identifier, under the transmission group is defined. By
convention, the name assigned is:
type OBJECT IDENTIFIER ::= { transmission number }
where "type" is the symbolic value used for the media in the ifType
column of the ifTable object, and "number" is the actual integer
value corresponding to the symbol.
3.13. The SNMP Group
The application-oriented working groups of the IETF have been tasked
to be receptive towards defining MIB variables specific to their
respective applications.
For the SNMP, it is useful to have statistical information. A new
group, the SNMP group, is allocated for this purpose:
snmp OBJECT IDENTIFIER ::= { mib-2 11 }
SNMP Working Group [Page 8]

RFC 1213 MIB-II March 19913.14. Changes from RFC 1158
Features of this MIB include:
(1) The managed objects in this document have been defined
using the conventions defined in the Internet-standard
SMI, as amended by the extensions specified in [14]. It
must be emphasized that definitions made using these
extensions are semantically identically to those in RFC1158.
(2) The PhysAddress textual convention has been introduced to
represent media addresses.
(3) The ACCESS clause of sysLocation is now read-write.
(4) The definition of sysServices has been clarified.
(5) New ifType values (29-32) have been defined. In
addition, the textual-descriptor for the DS1 and E1
interface types has been corrected.
(6) The definition of ipForwarding has been clarified.
(7) The definition of ipRouteType has been clarified.
(8) The ipRouteMetric5 and ipRouteInfo objects have been
defined.
(9) The ACCESS clause of tcpConnState is now read-write, to
support deletion of the TCB associated with a TCP
connection. The definition of this object has been
clarified to explain this usage.
(10) The definition of egpNeighEventTrigger has been
clarified.
(11) The definition of several of the variables in the new
snmp group have been clarified. In addition, the
snmpInBadTypes and snmpOutReadOnlys objects are no longer
present. (However, the object identifiers associated
with those objects are reserved to prevent future use.)
(12) The definition of snmpInReadOnlys has been clarified.
(13) The textual descriptor of the snmpEnableAuthTraps has
been changed to snmpEnableAuthenTraps, and the definition
has been clarified.
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RFC 1213 MIB-II March 1991
(14) The ipRoutingDiscards object was added.
(15) The optional use of an implementation-dependent, small
positive integer was disallowed when identifying
instances of the IP address and routing tables.
4. Objects
Managed objects are accessed via a virtual information store, termed
the Management Information Base or MIB. Objects in the MIB are
defined using the subset of Abstract Syntax Notation One (ASN.1) [8]
defined in the SMI. In particular, each object has a name, a syntax,
and an encoding. The name is an object identifier, an
administratively assigned name, which specifies an object type. The
object type together with an object instance serves to uniquely
identify a specific instantiation of the object. For human
convenience, we often use a textual string, termed the OBJECT
DESCRIPTOR, to also refer to the object type.
The syntax of an object type defines the abstract data structure
corresponding to that object type. The ASN.1 language is used for
this purpose. However, the SMI [12] purposely restricts the ASN.1
constructs which may be used. These restrictions are explicitly made
for simplicity.
The encoding of an object type is simply how that object type is
represented using the object type's syntax. Implicitly tied to the
notion of an object type's syntax and encoding is how the object type
is represented when being transmitted on the network.
The SMI specifies the use of the basic encoding rules of ASN.1 [9],
subject to the additional requirements imposed by the SNMP.
4.1. Format of DefinitionsSection 6 contains contains the specification of all object types
contained in this MIB module. The object types are defined using the
conventions defined in the SMI, as amended by the extensions
specified in [14].
5. Overview
Consistent with the IAB directive to produce simple, workable systems
in the short-term, the list of managed objects defined here, has been
derived by taking only those elements which are considered essential.
This approach of taking only the essential objects is NOT
restrictive, since the SMI defined in the companion memo provides
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RFC 1213 MIB-II March 1991
three extensibility mechanisms: one, the addition of new standard
objects through the definitions of new versions of the MIB; two, the
addition of widely-available but non-standard objects through the
experimental subtree; and three, the addition of private objects
through the enterprises subtree. Such additional objects can not
only be used for vendor-specific elements, but also for
experimentation as required to further the knowledge of which other
objects are essential.
The design of MIB-II is heavily influenced by the first extensibility
mechanism. Several new variables have been added based on
operational experience and need. Based on this, the criteria for
including an object in MIB-II are remarkably similar to the MIB-I
criteria:
(1) An object needed to be essential for either fault or
configuration management.
(2) Only weak control objects were permitted (by weak, it is
meant that tampering with them can do only limited
damage). This criterion reflects the fact that the
current management protocols are not sufficiently secure
to do more powerful control operations.
(3) Evidence of current use and utility was required.
(4) In MIB-I, an attempt was made to limit the number of
objects to about 100 to make it easier for vendors to
fully instrument their software. In MIB-II, this limit
was raised given the wide technological base now
implementing MIB-I.
(5) To avoid redundant variables, it was required that no
object be included that can be derived from others in the
MIB.
(6) Implementation specific objects (e.g., for BSD UNIX) were
excluded.
(7) It was agreed to avoid heavily instrumenting critical
sections of code. The general guideline was one counter
per critical section per layer.
MIB-II, like its predecessor, the Internet-standard MIB, contains
only essential elements. There is no need to allow individual
objects to be optional. Rather, the objects are arranged into the
following groups:
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RFC 1213 MIB-II March 1991
- System
- Interfaces
- Address Translation (deprecated)
- IP
- ICMP
- TCP
- UDP
- EGP
- Transmission
- SNMP
These groups are the basic unit of conformance: This method is as
follows: if the semantics of a group is applicable to an
implementation, then it must implement all objects in that group.
For example, an implementation must implement the EGP group if and
only if it implements the EGP.
There are two reasons for defining these groups: to provide a means
of assigning object identifiers; and, to provide a method for
implementations of managed agents to know which objects they must
implement.
6. DefinitionsRFC1213-MIB DEFINITIONS ::= BEGIN
IMPORTS
mgmt, NetworkAddress, IpAddress, Counter, Gauge,
TimeTicks
FROM RFC1155-SMI
OBJECT-TYPE
FROM RFC-1212;
-- This MIB module uses the extended OBJECT-TYPE macro as
-- defined in [14];
-- MIB-II (same prefix as MIB-I)
mib-2 OBJECT IDENTIFIER ::= { mgmt 1 }
-- textual conventions
DisplayString ::=
OCTET STRING
-- This data type is used to model textual information taken
-- from the NVT ASCII character set. By convention, objects
-- with this syntax are declared as having
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RFC 1213 MIB-II March 1991
DESCRIPTION
"A textual description of the entity. This value
should include the full name and version
identification of the system's hardware type,
software operating-system, and networking
software. It is mandatory that this only contain
printable ASCII characters."
::= { system 1 }
sysObjectID OBJECT-TYPE
SYNTAX OBJECT IDENTIFIER
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The vendor's authoritative identification of the
network management subsystem contained in the
entity. This value is allocated within the SMI
enterprises subtree (1.3.6.1.4.1) and provides an
easy and unambiguous means for determining `what
kind of box' is being managed. For example, if
vendor `Flintstones, Inc.' was assigned the
subtree 1.3.6.1.4.1.4242, it could assign the
identifier 1.3.6.1.4.1.4242.1.1 to its `Fred
Router'."
::= { system 2 }
sysUpTime OBJECT-TYPE
SYNTAX TimeTicks
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The time (in hundredths of a second) since the
network management portion of the system was last
re-initialized."
::= { system 3 }
sysContact OBJECT-TYPE
SYNTAX DisplayString (SIZE (0..255))
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The textual identification of the contact person
for this managed node, together with information
on how to contact this person."
::= { system 4 }
sysName OBJECT-TYPE
SYNTAX DisplayString (SIZE (0..255))
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RFC 1213 MIB-II March 1991
ACCESS read-write
STATUS mandatory
DESCRIPTION
"An administratively-assigned name for this
managed node. By convention, this is the node's
fully-qualified domain name."
::= { system 5 }
sysLocation OBJECT-TYPE
SYNTAX DisplayString (SIZE (0..255))
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The physical location of this node (e.g.,
`telephone closet, 3rd floor')."
::= { system 6 }
sysServices OBJECT-TYPE
SYNTAX INTEGER (0..127)
ACCESS read-only
STATUS mandatory
DESCRIPTION
"A value which indicates the set of services that
this entity primarily offers.
The value is a sum. This sum initially takes the
value zero, Then, for each layer, L, in the range
1 through 7, that this node performs transactions
for, 2 raised to (L - 1) is added to the sum. For
example, a node which performs primarily routing
functions would have a value of 4 (2^(3-1)). In
contrast, a node which is a host offering
application services would have a value of 72
(2^(4-1) + 2^(7-1)). Note that in the context of
the Internet suite of protocols, values should be
calculated accordingly:
layer functionality
1 physical (e.g., repeaters)
2 datalink/subnetwork (e.g., bridges)
3 internet (e.g., IP gateways)
4 end-to-end (e.g., IP hosts)
7 applications (e.g., mail relays)
For systems including OSI protocols, layers 5 and
6 may also be counted."
::= { system 7 }
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RFC 1213 MIB-II March 1991
-- the Interfaces group
-- Implementation of the Interfaces group is mandatory for
-- all systems.
ifNumber OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of network interfaces (regardless of
their current state) present on this system."
::= { interfaces 1 }
-- the Interfaces table
-- The Interfaces table contains information on the entity's
-- interfaces. Each interface is thought of as being
-- attached to a `subnetwork'. Note that this term should
-- not be confused with `subnet' which refers to an
-- addressing partitioning scheme used in the Internet suite
-- of protocols.
ifTable OBJECT-TYPE
SYNTAX SEQUENCE OF IfEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"A list of interface entries. The number of
entries is given by the value of ifNumber."
::= { interfaces 2 }
ifEntry OBJECT-TYPE
SYNTAX IfEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"An interface entry containing objects at the
subnetwork layer and below for a particular
interface."
INDEX { ifIndex }
::= { ifTable 1 }
IfEntry ::=
SEQUENCE {
ifIndex
INTEGER,
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RFC 1213 MIB-II March 1991
DESCRIPTION
"A unique value for each interface. Its value
ranges between 1 and the value of ifNumber. The
value for each interface must remain constant at
least from one re-initialization of the entity's
network management system to the next re-
initialization."
::= { ifEntry 1 }
ifDescr OBJECT-TYPE
SYNTAX DisplayString (SIZE (0..255))
ACCESS read-only
STATUS mandatory
DESCRIPTION
"A textual string containing information about the
interface. This string should include the name of
the manufacturer, the product name and the version
of the hardware interface."
::= { ifEntry 2 }
ifType OBJECT-TYPE
SYNTAX INTEGER {
other(1), -- none of the following
regular1822(2),
hdh1822(3),
ddn-x25(4),
rfc877-x25(5),
ethernet-csmacd(6),
iso88023-csmacd(7),
iso88024-tokenBus(8),
iso88025-tokenRing(9),
iso88026-man(10),
starLan(11),
proteon-10Mbit(12),
proteon-80Mbit(13),
hyperchannel(14),
fddi(15),
lapb(16),
sdlc(17),
ds1(18), -- T-1
e1(19), -- european equiv. of T-1
basicISDN(20),
primaryISDN(21), -- proprietary serial
propPointToPointSerial(22),
ppp(23),
softwareLoopback(24),
eon(25), -- CLNP over IP [11]
ethernet-3Mbit(26),
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RFC 1213 MIB-II March 1991
nsip(27), -- XNS over IP
slip(28), -- generic SLIP
ultra(29), -- ULTRA technologies
ds3(30), -- T-3
sip(31), -- SMDS
frame-relay(32)
}
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The type of interface, distinguished according to
the physical/link protocol(s) immediately `below'
the network layer in the protocol stack."
::= { ifEntry 3 }
ifMtu OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The size of the largest datagram which can be
sent/received on the interface, specified in
octets. For interfaces that are used for
transmitting network datagrams, this is the size
of the largest network datagram that can be sent
on the interface."
::= { ifEntry 4 }
ifSpeed OBJECT-TYPE
SYNTAX Gauge
ACCESS read-only
STATUS mandatory
DESCRIPTION
"An estimate of the interface's current bandwidth
in bits per second. For interfaces which do not
vary in bandwidth or for those where no accurate
estimation can be made, this object should contain
the nominal bandwidth."
::= { ifEntry 5 }
ifPhysAddress OBJECT-TYPE
SYNTAX PhysAddress
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The interface's address at the protocol layer
immediately `below' the network layer in the
protocol stack. For interfaces which do not have
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RFC 1213 MIB-II March 1991
such an address (e.g., a serial line), this object
should contain an octet string of zero length."
::= { ifEntry 6 }
ifAdminStatus OBJECT-TYPE
SYNTAX INTEGER {
up(1), -- ready to pass packets
down(2),
testing(3) -- in some test mode
}
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The desired state of the interface. The
testing(3) state indicates that no operational
packets can be passed."
::= { ifEntry 7 }
ifOperStatus OBJECT-TYPE
SYNTAX INTEGER {
up(1), -- ready to pass packets
down(2),
testing(3) -- in some test mode
}
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The current operational state of the interface.
The testing(3) state indicates that no operational
packets can be passed."
::= { ifEntry 8 }
ifLastChange OBJECT-TYPE
SYNTAX TimeTicks
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The value of sysUpTime at the time the interface
entered its current operational state. If the
current state was entered prior to the last re-
initialization of the local network management
subsystem, then this object contains a zero
value."
::= { ifEntry 9 }
ifInOctets OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
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RFC 1213 MIB-II March 1991
STATUS mandatory
DESCRIPTION
"The total number of octets received on the
interface, including framing characters."
::= { ifEntry 10 }
ifInUcastPkts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of subnetwork-unicast packets
delivered to a higher-layer protocol."
::= { ifEntry 11 }
ifInNUcastPkts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of non-unicast (i.e., subnetwork-
broadcast or subnetwork-multicast) packets
delivered to a higher-layer protocol."
::= { ifEntry 12 }
ifInDiscards OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of inbound packets which were chosen
to be discarded even though no errors had been
detected to prevent their being deliverable to a
higher-layer protocol. One possible reason for
discarding such a packet could be to free up
buffer space."
::= { ifEntry 13 }
ifInErrors OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of inbound packets that contained
errors preventing them from being deliverable to a
higher-layer protocol."
::= { ifEntry 14 }
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RFC 1213 MIB-II March 1991
ifInUnknownProtos OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of packets received via the interface
which were discarded because of an unknown or
unsupported protocol."
::= { ifEntry 15 }
ifOutOctets OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of octets transmitted out of the
interface, including framing characters."
::= { ifEntry 16 }
ifOutUcastPkts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of packets that higher-level
protocols requested be transmitted to a
subnetwork-unicast address, including those that
were discarded or not sent."
::= { ifEntry 17 }
ifOutNUcastPkts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of packets that higher-level
protocols requested be transmitted to a non-
unicast (i.e., a subnetwork-broadcast or
subnetwork-multicast) address, including those
that were discarded or not sent."
::= { ifEntry 18 }
ifOutDiscards OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of outbound packets which were chosen
SNMP Working Group [Page 22]

RFC 1213 MIB-II March 1991
to be discarded even though no errors had been
detected to prevent their being transmitted. One
possible reason for discarding such a packet could
be to free up buffer space."
::= { ifEntry 19 }
ifOutErrors OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of outbound packets that could not be
transmitted because of errors."
::= { ifEntry 20 }
ifOutQLen OBJECT-TYPE
SYNTAX Gauge
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The length of the output packet queue (in
packets)."
::= { ifEntry 21 }
ifSpecific OBJECT-TYPE
SYNTAX OBJECT IDENTIFIER
ACCESS read-only
STATUS mandatory
DESCRIPTION
"A reference to MIB definitions specific to the
particular media being used to realize the
interface. For example, if the interface is
realized by an ethernet, then the value of this
object refers to a document defining objects
specific to ethernet. If this information is not
present, its value should be set to the OBJECT
IDENTIFIER { 0 0 }, which is a syntatically valid
object identifier, and any conformant
implementation of ASN.1 and BER must be able to
generate and recognize this value."
::= { ifEntry 22 }
-- the Address Translation group
-- Implementation of the Address Translation group is
-- mandatory for all systems. Note however that this group
-- is deprecated by MIB-II. That is, it is being included
SNMP Working Group [Page 23]

RFC 1213 MIB-II March 1991
-- solely for compatibility with MIB-I nodes, and will most
-- likely be excluded from MIB-III nodes. From MIB-II and
-- onwards, each network protocol group contains its own
-- address translation tables.
-- The Address Translation group contains one table which is
-- the union across all interfaces of the translation tables
-- for converting a NetworkAddress (e.g., an IP address) into
-- a subnetwork-specific address. For lack of a better term,
-- this document refers to such a subnetwork-specific address
-- as a `physical' address.
-- Examples of such translation tables are: for broadcast
-- media where ARP is in use, the translation table is
-- equivalent to the ARP cache; or, on an X.25 network where
-- non-algorithmic translation to X.121 addresses is
-- required, the translation table contains the
-- NetworkAddress to X.121 address equivalences.
atTable OBJECT-TYPE
SYNTAX SEQUENCE OF AtEntry
ACCESS not-accessible
STATUS deprecated
DESCRIPTION
"The Address Translation tables contain the
NetworkAddress to `physical' address equivalences.
Some interfaces do not use translation tables for
determining address equivalences (e.g., DDN-X.25
has an algorithmic method); if all interfaces are
of this type, then the Address Translation table
is empty, i.e., has zero entries."
::= { at 1 }
atEntry OBJECT-TYPE
SYNTAX AtEntry
ACCESS not-accessible
STATUS deprecated
DESCRIPTION
"Each entry contains one NetworkAddress to
`physical' address equivalence."
INDEX { atIfIndex,
atNetAddress }
::= { atTable 1 }
AtEntry ::=
SEQUENCE {
atIfIndex
INTEGER,
SNMP Working Group [Page 24]

RFC 1213 MIB-II March 1991
atPhysAddress
PhysAddress,
atNetAddress
NetworkAddress
}
atIfIndex OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-write
STATUS deprecated
DESCRIPTION
"The interface on which this entry's equivalence
is effective. The interface identified by a
particular value of this index is the same
interface as identified by the same value of
ifIndex."
::= { atEntry 1 }
atPhysAddress OBJECT-TYPE
SYNTAX PhysAddress
ACCESS read-write
STATUS deprecated
DESCRIPTION
"The media-dependent `physical' address.
Setting this object to a null string (one of zero
length) has the effect of invaliding the
corresponding entry in the atTable object. That
is, it effectively dissasociates the interface
identified with said entry from the mapping
identified with said entry. It is an
implementation-specific matter as to whether the
agent removes an invalidated entry from the table.
Accordingly, management stations must be prepared
to receive tabular information from agents that
corresponds to entries not currently in use.
Proper interpretation of such entries requires
examination of the relevant atPhysAddress object."
::= { atEntry 2 }
atNetAddress OBJECT-TYPE
SYNTAX NetworkAddress
ACCESS read-write
STATUS deprecated
DESCRIPTION
"The NetworkAddress (e.g., the IP address)
corresponding to the media-dependent `physical'
address."
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RFC 1213 MIB-II March 1991
::= { atEntry 3 }
-- the IP group
-- Implementation of the IP group is mandatory for all
-- systems.
ipForwarding OBJECT-TYPE
SYNTAX INTEGER {
forwarding(1), -- acting as a gateway
not-forwarding(2) -- NOT acting as a gateway
}
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The indication of whether this entity is acting
as an IP gateway in respect to the forwarding of
datagrams received by, but not addressed to, this
entity. IP gateways forward datagrams. IP hosts
do not (except those source-routed via the host).
Note that for some managed nodes, this object may
take on only a subset of the values possible.
Accordingly, it is appropriate for an agent to
return a `badValue' response if a management
station attempts to change this object to an
inappropriate value."
::= { ip 1 }
ipDefaultTTL OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The default value inserted into the Time-To-Live
field of the IP header of datagrams originated at
this entity, whenever a TTL value is not supplied
by the transport layer protocol."
::= { ip 2 }
ipInReceives OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of input datagrams received from
interfaces, including those received in error."
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RFC 1213 MIB-II March 1991
::= { ip 3 }
ipInHdrErrors OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of input datagrams discarded due to
errors in their IP headers, including bad
checksums, version number mismatch, other format
errors, time-to-live exceeded, errors discovered
in processing their IP options, etc."
::= { ip 4 }
ipInAddrErrors OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of input datagrams discarded because
the IP address in their IP header's destination
field was not a valid address to be received at
this entity. This count includes invalid
addresses (e.g., 0.0.0.0) and addresses of
unsupported Classes (e.g., Class E). For entities
which are not IP Gateways and therefore do not
forward datagrams, this counter includes datagrams
discarded because the destination address was not
a local address."
::= { ip 5 }
ipForwDatagrams OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of input datagrams for which this
entity was not their final IP destination, as a
result of which an attempt was made to find a
route to forward them to that final destination.
In entities which do not act as IP Gateways, this
counter will include only those packets which were
Source-Routed via this entity, and the Source-
Route option processing was successful."
::= { ip 6 }
ipInUnknownProtos OBJECT-TYPE
SYNTAX Counter
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RFC 1213 MIB-II March 1991
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of locally-addressed datagrams
received successfully but discarded because of an
unknown or unsupported protocol."
::= { ip 7 }
ipInDiscards OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of input IP datagrams for which no
problems were encountered to prevent their
continued processing, but which were discarded
(e.g., for lack of buffer space). Note that this
counter does not include any datagrams discarded
while awaiting re-assembly."
::= { ip 8 }
ipInDelivers OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of input datagrams successfully
delivered to IP user-protocols (including ICMP)."
::= { ip 9 }
ipOutRequests OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of IP datagrams which local IP
user-protocols (including ICMP) supplied to IP in
requests for transmission. Note that this counter
does not include any datagrams counted in
ipForwDatagrams."
::= { ip 10 }
ipOutDiscards OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of output IP datagrams for which no
SNMP Working Group [Page 28]

RFC 1213 MIB-II March 1991
problem was encountered to prevent their
transmission to their destination, but which were
discarded (e.g., for lack of buffer space). Note
that this counter would include datagrams counted
in ipForwDatagrams if any such packets met this
(discretionary) discard criterion."
::= { ip 11 }
ipOutNoRoutes OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of IP datagrams discarded because no
route could be found to transmit them to their
destination. Note that this counter includes any
packets counted in ipForwDatagrams which meet this
`no-route' criterion. Note that this includes any
datagarms which a host cannot route because all of
its default gateways are down."
::= { ip 12 }
ipReasmTimeout OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The maximum number of seconds which received
fragments are held while they are awaiting
reassembly at this entity."
::= { ip 13 }
ipReasmReqds OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of IP fragments received which needed
to be reassembled at this entity."
::= { ip 14 }
ipReasmOKs OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of IP datagrams successfully re-
assembled."
SNMP Working Group [Page 29]

RFC 1213 MIB-II March 1991
::= { ip 15 }
ipReasmFails OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of failures detected by the IP re-
assembly algorithm (for whatever reason: timed
out, errors, etc). Note that this is not
necessarily a count of discarded IP fragments
since some algorithms (notably the algorithm in
RFC 815) can lose track of the number of fragments
by combining them as they are received."
::= { ip 16 }
ipFragOKs OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of IP datagrams that have been
successfully fragmented at this entity."
::= { ip 17 }
ipFragFails OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of IP datagrams that have been
discarded because they needed to be fragmented at
this entity but could not be, e.g., because their
Don't Fragment flag was set."
::= { ip 18 }
ipFragCreates OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of IP datagram fragments that have
been generated as a result of fragmentation at
this entity."
::= { ip 19 }
SNMP Working Group [Page 30]

RFC 1213 MIB-II March 1991
ipAdEntIfIndex OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The index value which uniquely identifies the
interface to which this entry is applicable. The
interface identified by a particular value of this
index is the same interface as identified by the
same value of ifIndex."
::= { ipAddrEntry 2 }
ipAdEntNetMask OBJECT-TYPE
SYNTAX IpAddress
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The subnet mask associated with the IP address of
this entry. The value of the mask is an IP
address with all the network bits set to 1 and all
the hosts bits set to 0."
::= { ipAddrEntry 3 }
ipAdEntBcastAddr OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The value of the least-significant bit in the IP
broadcast address used for sending datagrams on
the (logical) interface associated with the IP
address of this entry. For example, when the
Internet standard all-ones broadcast address is
used, the value will be 1. This value applies to
both the subnet and network broadcasts addresses
used by the entity on this (logical) interface."
::= { ipAddrEntry 4 }
ipAdEntReasmMaxSize OBJECT-TYPE
SYNTAX INTEGER (0..65535)
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The size of the largest IP datagram which this
entity can re-assemble from incoming IP fragmented
datagrams received on this interface."
::= { ipAddrEntry 5 }
SNMP Working Group [Page 32]

RFC 1213 MIB-II March 1991
ipRouteInfo
OBJECT IDENTIFIER
}
ipRouteDest OBJECT-TYPE
SYNTAX IpAddress
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The destination IP address of this route. An
entry with a value of 0.0.0.0 is considered a
default route. Multiple routes to a single
destination can appear in the table, but access to
such multiple entries is dependent on the table-
access mechanisms defined by the network
management protocol in use."
::= { ipRouteEntry 1 }
ipRouteIfIndex OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The index value which uniquely identifies the
local interface through which the next hop of this
route should be reached. The interface identified
by a particular value of this index is the same
interface as identified by the same value of
ifIndex."
::= { ipRouteEntry 2 }
ipRouteMetric1 OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The primary routing metric for this route. The
semantics of this metric are determined by the
routing-protocol specified in the route's
ipRouteProto value. If this metric is not used,
its value should be set to -1."
::= { ipRouteEntry 3 }
ipRouteMetric2 OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-write
STATUS mandatory
DESCRIPTION
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RFC 1213 MIB-II March 1991
"An alternate routing metric for this route. The
semantics of this metric are determined by the
routing-protocol specified in the route's
ipRouteProto value. If this metric is not used,
its value should be set to -1."
::= { ipRouteEntry 4 }
ipRouteMetric3 OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-write
STATUS mandatory
DESCRIPTION
"An alternate routing metric for this route. The
semantics of this metric are determined by the
routing-protocol specified in the route's
ipRouteProto value. If this metric is not used,
its value should be set to -1."
::= { ipRouteEntry 5 }
ipRouteMetric4 OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-write
STATUS mandatory
DESCRIPTION
"An alternate routing metric for this route. The
semantics of this metric are determined by the
routing-protocol specified in the route's
ipRouteProto value. If this metric is not used,
its value should be set to -1."
::= { ipRouteEntry 6 }
ipRouteNextHop OBJECT-TYPE
SYNTAX IpAddress
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The IP address of the next hop of this route.
(In the case of a route bound to an interface
which is realized via a broadcast media, the value
of this field is the agent's IP address on that
interface.)"
::= { ipRouteEntry 7 }
ipRouteType OBJECT-TYPE
SYNTAX INTEGER {
other(1), -- none of the following
invalid(2), -- an invalidated route
SNMP Working Group [Page 35]

RFC 1213 MIB-II March 1991
-- route to directly
direct(3), -- connected (sub-)network
-- route to a non-local
indirect(4) -- host/network/sub-network
}
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The type of route. Note that the values
direct(3) and indirect(4) refer to the notion of
direct and indirect routing in the IP
architecture.
Setting this object to the value invalid(2) has
the effect of invalidating the corresponding entry
in the ipRouteTable object. That is, it
effectively dissasociates the destination
identified with said entry from the route
identified with said entry. It is an
implementation-specific matter as to whether the
agent removes an invalidated entry from the table.
Accordingly, management stations must be prepared
to receive tabular information from agents that
corresponds to entries not currently in use.
Proper interpretation of such entries requires
examination of the relevant ipRouteType object."
::= { ipRouteEntry 8 }
ipRouteProto OBJECT-TYPE
SYNTAX INTEGER {
other(1), -- none of the following
-- non-protocol information,
-- e.g., manually configured
local(2), -- entries
-- set via a network
netmgmt(3), -- management protocol
-- obtained via ICMP,
icmp(4), -- e.g., Redirect
-- the remaining values are
-- all gateway routing
-- protocols
egp(5),
ggp(6),
SNMP Working Group [Page 36]

RFC 1213 MIB-II March 1991
hello(7),
rip(8),
is-is(9),
es-is(10),
ciscoIgrp(11),
bbnSpfIgp(12),
ospf(13),
bgp(14)
}
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The routing mechanism via which this route was
learned. Inclusion of values for gateway routing
protocols is not intended to imply that hosts
should support those protocols."
::= { ipRouteEntry 9 }
ipRouteAge OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The number of seconds since this route was last
updated or otherwise determined to be correct.
Note that no semantics of `too old' can be implied
except through knowledge of the routing protocol
by which the route was learned."
::= { ipRouteEntry 10 }
ipRouteMask OBJECT-TYPE
SYNTAX IpAddress
ACCESS read-write
STATUS mandatory
DESCRIPTION
"Indicate the mask to be logical-ANDed with the
destination address before being compared to the
value in the ipRouteDest field. For those systems
that do not support arbitrary subnet masks, an
agent constructs the value of the ipRouteMask by
determining whether the value of the correspondent
ipRouteDest field belong to a class-A, B, or C
network, and then using one of:
mask network
255.0.0.0 class-A
255.255.0.0 class-B
255.255.255.0 class-C
SNMP Working Group [Page 37]

RFC 1213 MIB-II March 1991
If the value of the ipRouteDest is 0.0.0.0 (a
default route), then the mask value is also
0.0.0.0. It should be noted that all IP routing
subsystems implicitly use this mechanism."
::= { ipRouteEntry 11 }
ipRouteMetric5 OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-write
STATUS mandatory
DESCRIPTION
"An alternate routing metric for this route. The
semantics of this metric are determined by the
routing-protocol specified in the route's
ipRouteProto value. If this metric is not used,
its value should be set to -1."
::= { ipRouteEntry 12 }
ipRouteInfo OBJECT-TYPE
SYNTAX OBJECT IDENTIFIER
ACCESS read-only
STATUS mandatory
DESCRIPTION
"A reference to MIB definitions specific to the
particular routing protocol which is responsible
for this route, as determined by the value
specified in the route's ipRouteProto value. If
this information is not present, its value should
be set to the OBJECT IDENTIFIER { 0 0 }, which is
a syntatically valid object identifier, and any
conformant implementation of ASN.1 and BER must be
able to generate and recognize this value."
::= { ipRouteEntry 13 }
-- the IP Address Translation table
-- The IP address translation table contain the IpAddress to
-- `physical' address equivalences. Some interfaces do not
-- use translation tables for determining address
-- equivalences (e.g., DDN-X.25 has an algorithmic method);
-- if all interfaces are of this type, then the Address
-- Translation table is empty, i.e., has zero entries.
ipNetToMediaTable OBJECT-TYPE
SYNTAX SEQUENCE OF IpNetToMediaEntry
ACCESS not-accessible
STATUS mandatory
SNMP Working Group [Page 38]

RFC 1213 MIB-II March 1991
ipNetToMediaNetAddress OBJECT-TYPE
SYNTAX IpAddress
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The IpAddress corresponding to the media-
dependent `physical' address."
::= { ipNetToMediaEntry 3 }
ipNetToMediaType OBJECT-TYPE
SYNTAX INTEGER {
other(1), -- none of the following
invalid(2), -- an invalidated mapping
dynamic(3),
static(4)
}
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The type of mapping.
Setting this object to the value invalid(2) has
the effect of invalidating the corresponding entry
in the ipNetToMediaTable. That is, it effectively
dissasociates the interface identified with said
entry from the mapping identified with said entry.
It is an implementation-specific matter as to
whether the agent removes an invalidated entry
from the table. Accordingly, management stations
must be prepared to receive tabular information
from agents that corresponds to entries not
currently in use. Proper interpretation of such
entries requires examination of the relevant
ipNetToMediaType object."
::= { ipNetToMediaEntry 4 }
-- additional IP objects
ipRoutingDiscards OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of routing entries which were chosen
to be discarded even though they are valid. One
possible reason for discarding such an entry could
be to free-up buffer space for other routing
SNMP Working Group [Page 40]

RFC 1213 MIB-II March 1991
icmpOutAddrMaskReps OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of ICMP Address Mask Reply messages
sent."
::= { icmp 26 }
-- the TCP group
-- Implementation of the TCP group is mandatory for all
-- systems that implement the TCP.
-- Note that instances of object types that represent
-- information about a particular TCP connection are
-- transient; they persist only as long as the connection
-- in question.
tcpRtoAlgorithm OBJECT-TYPE
SYNTAX INTEGER {
other(1), -- none of the following
constant(2), -- a constant rto
rsre(3), -- MIL-STD-1778, Appendix B
vanj(4) -- Van Jacobson's algorithm [10]
}
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The algorithm used to determine the timeout value
used for retransmitting unacknowledged octets."
::= { tcp 1 }
tcpRtoMin OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The minimum value permitted by a TCP
implementation for the retransmission timeout,
measured in milliseconds. More refined semantics
for objects of this type depend upon the algorithm
used to determine the retransmission timeout. In
particular, when the timeout algorithm is rsre(3),
an object of this type has the semantics of the
LBOUND quantity described in RFC 793."
SNMP Working Group [Page 46]

RFC 1213 MIB-II March 1991
::= { tcp 2 }
tcpRtoMax OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The maximum value permitted by a TCP
implementation for the retransmission timeout,
measured in milliseconds. More refined semantics
for objects of this type depend upon the algorithm
used to determine the retransmission timeout. In
particular, when the timeout algorithm is rsre(3),
an object of this type has the semantics of the
UBOUND quantity described in RFC 793."
::= { tcp 3 }
tcpMaxConn OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The limit on the total number of TCP connections
the entity can support. In entities where the
maximum number of connections is dynamic, this
object should contain the value -1."
::= { tcp 4 }
tcpActiveOpens OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of times TCP connections have made a
direct transition to the SYN-SENT state from the
CLOSED state."
::= { tcp 5 }
tcpPassiveOpens OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of times TCP connections have made a
direct transition to the SYN-RCVD state from the
LISTEN state."
::= { tcp 6 }
SNMP Working Group [Page 47]

RFC 1213 MIB-II March 1991
tcpAttemptFails OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of times TCP connections have made a
direct transition to the CLOSED state from either
the SYN-SENT state or the SYN-RCVD state, plus the
number of times TCP connections have made a direct
transition to the LISTEN state from the SYN-RCVD
state."
::= { tcp 7 }
tcpEstabResets OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of times TCP connections have made a
direct transition to the CLOSED state from either
the ESTABLISHED state or the CLOSE-WAIT state."
::= { tcp 8 }
tcpCurrEstab OBJECT-TYPE
SYNTAX Gauge
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of TCP connections for which the
current state is either ESTABLISHED or CLOSE-
WAIT."
::= { tcp 9 }
tcpInSegs OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of segments received, including
those received in error. This count includes
segments received on currently established
connections."
::= { tcp 10 }
tcpOutSegs OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
SNMP Working Group [Page 48]

RFC 1213 MIB-II March 1991
TcpConnEntry ::=
SEQUENCE {
tcpConnState
INTEGER,
tcpConnLocalAddress
IpAddress,
tcpConnLocalPort
INTEGER (0..65535),
tcpConnRemAddress
IpAddress,
tcpConnRemPort
INTEGER (0..65535)
}
tcpConnState OBJECT-TYPE
SYNTAX INTEGER {
closed(1),
listen(2),
synSent(3),
synReceived(4),
established(5),
finWait1(6),
finWait2(7),
closeWait(8),
lastAck(9),
closing(10),
timeWait(11),
deleteTCB(12)
}
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The state of this TCP connection.
The only value which may be set by a management
station is deleteTCB(12). Accordingly, it is
appropriate for an agent to return a `badValue'
response if a management station attempts to set
this object to any other value.
If a management station sets this object to the
value deleteTCB(12), then this has the effect of
deleting the TCB (as defined in RFC 793) of the
corresponding connection on the managed node,
resulting in immediate termination of the
connection.
As an implementation-specific option, a RST
SNMP Working Group [Page 50]

RFC 1213 MIB-II March 1991
DESCRIPTION
"The total number of segments received in error
(e.g., bad TCP checksums)."
::= { tcp 14 }
tcpOutRsts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of TCP segments sent containing the
RST flag."
::= { tcp 15 }
-- the UDP group
-- Implementation of the UDP group is mandatory for all
-- systems which implement the UDP.
udpInDatagrams OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of UDP datagrams delivered to
UDP users."
::= { udp 1 }
udpNoPorts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of received UDP datagrams for
which there was no application at the destination
port."
::= { udp 2 }
udpInErrors OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of received UDP datagrams that could
not be delivered for reasons other than the lack
of an application at the destination port."
::= { udp 3 }
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RFC 1213 MIB-II March 1991
DESCRIPTION
"The number of EGP-defined error messages received
from this EGP peer."
::= { egpNeighEntry 8 }
egpNeighOutErrMsgs OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of EGP-defined error messages sent to
this EGP peer."
::= { egpNeighEntry 9 }
egpNeighStateUps OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of EGP state transitions to the UP
state with this EGP peer."
::= { egpNeighEntry 10 }
egpNeighStateDowns OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of EGP state transitions from the UP
state to any other state with this EGP peer."
::= { egpNeighEntry 11 }
egpNeighIntervalHello OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The interval between EGP Hello command
retransmissions (in hundredths of a second). This
represents the t1 timer as defined in RFC 904."
::= { egpNeighEntry 12 }
egpNeighIntervalPoll OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The interval between EGP poll command
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RFC 1213 MIB-II March 1991
retransmissions (in hundredths of a second). This
represents the t3 timer as defined in RFC 904."
::= { egpNeighEntry 13 }
egpNeighMode OBJECT-TYPE
SYNTAX INTEGER { active(1), passive(2) }
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The polling mode of this EGP entity, either
passive or active."
::= { egpNeighEntry 14 }
egpNeighEventTrigger OBJECT-TYPE
SYNTAX INTEGER { start(1), stop(2) }
ACCESS read-write
STATUS mandatory
DESCRIPTION
"A control variable used to trigger operator-
initiated Start and Stop events. When read, this
variable always returns the most recent value that
egpNeighEventTrigger was set to. If it has not
been set since the last initialization of the
network management subsystem on the node, it
returns a value of `stop'.
When set, this variable causes a Start or Stop
event on the specified neighbor, as specified on
pages 8-10 of RFC 904. Briefly, a Start event
causes an Idle peer to begin neighbor acquisition
and a non-Idle peer to reinitiate neighbor
acquisition. A stop event causes a non-Idle peer
to return to the Idle state until a Start event
occurs, either via egpNeighEventTrigger or
otherwise."
::= { egpNeighEntry 15 }
-- additional EGP objects
egpAs OBJECT-TYPE
SYNTAX INTEGER
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The autonomous system number of this EGP entity."
::= { egp 6 }
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RFC 1213 MIB-II March 1991
-- the Transmission group
-- Based on the transmission media underlying each interface
-- on a system, the corresponding portion of the Transmission
-- group is mandatory for that system.
-- When Internet-standard definitions for managing
-- transmission media are defined, the transmission group is
-- used to provide a prefix for the names of those objects.
-- Typically, such definitions reside in the experimental
-- portion of the MIB until they are "proven", then as a
-- part of the Internet standardization process, the
-- definitions are accordingly elevated and a new object
-- identifier, under the transmission group is defined. By
-- convention, the name assigned is:
--
-- type OBJECT IDENTIFIER ::= { transmission number }
--
-- where "type" is the symbolic value used for the media in
-- the ifType column of the ifTable object, and "number" is
-- the actual integer value corresponding to the symbol.
-- the SNMP group
-- Implementation of the SNMP group is mandatory for all
-- systems which support an SNMP protocol entity. Some of
-- the objects defined below will be zero-valued in those
-- SNMP implementations that are optimized to support only
-- those functions specific to either a management agent or
-- a management station. In particular, it should be
-- observed that the objects below refer to an SNMP entity,
-- and there may be several SNMP entities residing on a
-- managed node (e.g., if the node is hosting acting as
-- a management station).
snmpInPkts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of Messages delivered to the
SNMP entity from the transport service."
::= { snmp 1 }
snmpOutPkts OBJECT-TYPE
SYNTAX Counter
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RFC 1213 MIB-II March 1991
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of SNMP Messages which were
passed from the SNMP protocol entity to the
transport service."
::= { snmp 2 }
snmpInBadVersions OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of SNMP Messages which were
delivered to the SNMP protocol entity and were for
an unsupported SNMP version."
::= { snmp 3 }
snmpInBadCommunityNames OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of SNMP Messages delivered to
the SNMP protocol entity which used a SNMP
community name not known to said entity."
::= { snmp 4 }
snmpInBadCommunityUses OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of SNMP Messages delivered to
the SNMP protocol entity which represented an SNMP
operation which was not allowed by the SNMP
community named in the Message."
::= { snmp 5 }
snmpInASNParseErrs OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of ASN.1 or BER errors
encountered by the SNMP protocol entity when
decoding received SNMP Messages."
::= { snmp 6 }
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RFC 1213 MIB-II March 1991
-- { snmp 7 } is not used
snmpInTooBigs OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of SNMP PDUs which were
delivered to the SNMP protocol entity and for
which the value of the error-status field is
`tooBig'."
::= { snmp 8 }
snmpInNoSuchNames OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of SNMP PDUs which were
delivered to the SNMP protocol entity and for
which the value of the error-status field is
`noSuchName'."
::= { snmp 9 }
snmpInBadValues OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of SNMP PDUs which were
delivered to the SNMP protocol entity and for
which the value of the error-status field is
`badValue'."
::= { snmp 10 }
snmpInReadOnlys OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number valid SNMP PDUs which were
delivered to the SNMP protocol entity and for
which the value of the error-status field is
`readOnly'. It should be noted that it is a
protocol error to generate an SNMP PDU which
contains the value `readOnly' in the error-status
field, as such this object is provided as a means
of detecting incorrect implementations of the
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RFC 1213 MIB-II March 1991
SNMP."
::= { snmp 11 }
snmpInGenErrs OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of SNMP PDUs which were
delivered to the SNMP protocol entity and for
which the value of the error-status field is
`genErr'."
::= { snmp 12 }
snmpInTotalReqVars OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of MIB objects which have been
retrieved successfully by the SNMP protocol entity
as the result of receiving valid SNMP Get-Request
and Get-Next PDUs."
::= { snmp 13 }
snmpInTotalSetVars OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of MIB objects which have been
altered successfully by the SNMP protocol entity
as the result of receiving valid SNMP Set-Request
PDUs."
::= { snmp 14 }
snmpInGetRequests OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of SNMP Get-Request PDUs which
have been accepted and processed by the SNMP
protocol entity."
::= { snmp 15 }
snmpInGetNexts OBJECT-TYPE
SYNTAX Counter
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RFC 1213 MIB-II March 1991
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of SNMP Get-Next PDUs which have
been accepted and processed by the SNMP protocol
entity."
::= { snmp 16 }
snmpInSetRequests OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of SNMP Set-Request PDUs which
have been accepted and processed by the SNMP
protocol entity."
::= { snmp 17 }
snmpInGetResponses OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of SNMP Get-Response PDUs which
have been accepted and processed by the SNMP
protocol entity."
::= { snmp 18 }
snmpInTraps OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of SNMP Trap PDUs which have
been accepted and processed by the SNMP protocol
entity."
::= { snmp 19 }
snmpOutTooBigs OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of SNMP PDUs which were
generated by the SNMP protocol entity and for
which the value of the error-status field is
`tooBig.'"
::= { snmp 20 }
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RFC 1213 MIB-II March 1991
snmpOutNoSuchNames OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of SNMP PDUs which were
generated by the SNMP protocol entity and for
which the value of the error-status is
`noSuchName'."
::= { snmp 21 }
snmpOutBadValues OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of SNMP PDUs which were
generated by the SNMP protocol entity and for
which the value of the error-status field is
`badValue'."
::= { snmp 22 }
-- { snmp 23 } is not used
snmpOutGenErrs OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of SNMP PDUs which were
generated by the SNMP protocol entity and for
which the value of the error-status field is
`genErr'."
::= { snmp 24 }
snmpOutGetRequests OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of SNMP Get-Request PDUs which
have been generated by the SNMP protocol entity."
::= { snmp 25 }
snmpOutGetNexts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
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RFC 1213 MIB-II March 1991
DESCRIPTION
"The total number of SNMP Get-Next PDUs which have
been generated by the SNMP protocol entity."
::= { snmp 26 }
snmpOutSetRequests OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of SNMP Set-Request PDUs which
have been generated by the SNMP protocol entity."
::= { snmp 27 }
snmpOutGetResponses OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of SNMP Get-Response PDUs which
have been generated by the SNMP protocol entity."
::= { snmp 28 }
snmpOutTraps OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of SNMP Trap PDUs which have
been generated by the SNMP protocol entity."
::= { snmp 29 }
snmpEnableAuthenTraps OBJECT-TYPE
SYNTAX INTEGER { enabled(1), disabled(2) }
ACCESS read-write
STATUS mandatory
DESCRIPTION
"Indicates whether the SNMP agent process is
permitted to generate authentication-failure
traps. The value of this object overrides any
configuration information; as such, it provides a
means whereby all authentication-failure traps may
be disabled.
Note that it is strongly recommended that this
object be stored in non-volatile memory so that it
remains constant between re-initializations of the
network management system."
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